In a decayed tooth treating method, which is generally used in a dental clinic, a decayed portion of a tooth is first removed with drilling. When the pulp of the tooth is injured, the injured or affected pulp is also removed using an endodontic file. After the root canal has been prepared, the root canal is sealed with root canal filling materials. Finally, a prosthetic treatment is carried out on the tooth. In the root canal filling procedure, gutta-percha cones are used as a permanent filling material having an auxiliary function for enabling the filler, which is endodontic cement or a sealer, to penetrate into the root canal and thus to seal up the root canal. Gutta-percha, which is a natural vegetable extract, has a solid phase at room temperature, but has the form of a semisolid gum when it is compressed or heated. The gutta-percha having the form of such a solid gum for the root canal filling, is called “gutta-percha cone”.
Generally, gutta-percha cones are prepared by adding zinc oxide, barium sulfate, wax, and pigment to gutta-percha, kneading them into a paste in a mixer, extruding the paste in the form of a sheet using rollers, cutting the sheet into pieces, and shaping the pieces into a conical structure. Thus, gutta-percha cones having various sizes can be formed. The gutta-percha cone is widely used as a material for endodontic treatment because it is known to be most biologically compatible with living bodies and it is harmless to the root apexes of teeth. Gutta-percha cones, which are currently commercially available, are classified into a standardized cone and an accessory cone. The standardized cone has a shape identical to that of a dental file.
In endodontic treatment for a decayed tooth, the affected pulp of the tooth is first drilled to remove affected nerve tissues. After the root canal has been prepared, the root canal is sealed with root canal filling materials. For the root canal filling, a gutta-percha cone having a suitable size is then inserted into the root canal to fix with the filler, which is endodontic cement or a sealer, to the main and accessory portions of the root canal. Thereafter, a filler is coated on the root canal wall. In this case, it is important to bring the gutta-percha cone into complete contact with the root canal wall and apical area of the tooth in order to prevent the root canal from being further affected by a source of infected area.
After completion of the root canal filling procedure, the filling state in the root canal is confirmed using X-ray photography. The gutta-percha cone is then removed. For the removal of the gutta-percha cone, an excavator, an endodontic plugger, or a spreader is used in a state of being heated in flame.
Generally, the endodontic instrument for root canal filling includes a handpiece, and a control box which includes a power source for supplying electric power to the handpiece, and a controller for controlling the handpiece. The handpiece, which is grasped by a doctor for endodontic treatment, is separate from the control box and it is electrically connected with the control box by a cable.
Hereinafter, a conventional endodontic instrument for root canal filling will be described with reference to FIGS. 1 and 2.
FIG. 1 is a perspective view of a conventional endodontic instrument for root canal filling, and FIG. 2 is a sectional view of a heating tip in the conventional endodontic instrument for root canal filling illustrated in FIG. 1. Referring to FIGS. 1 and 2, the conventional endodontic filling instrument 100 includes a heating tip 110, a handpiece 120, a cable 130, and a control box 140. The control box 140 includes a power switch 142, a control panel 141, and a display (not shown) for displaying an operation state of the filling instrument 100. The handpiece 120 is connected to the heating tip 110 for supplying heat to gutta-percha to melt or cut the gutta-percha. The handpiece 120 and the control box 140 are connected to each other by the cable 130. Electric power required by the handpiece 120 is supplied from the control box 140 via the cable 30.
The heating tip 110 includes a heat generating core 114, an insulating film 112 enclosing the heat generating core 114, and a conical resistant heat generating layer 111 having a cross-sectional area gradually reduced toward a front end 113 of the heat generating core 114. The front end 113 of the heat generating core 114 is connected to the resistant heat generating layer 111 because it is not enclosed by the insulating film 112.
Accordingly, when a current flows through the resistant heat generating layer 111 and the heat generating core 114, a current density increases at the front end 113 where the heat generating core 114 and the resistant heat generating layer 111 are connected to each other, thus generating more heat than any portion.
However, the above-mentioned conventional filling instrument has a problem in that there is inconvenience in carrying the filling instrument because the control box and the handpiece are separate from each other. Further, the heating tip has poor heating efficiency.